Preparation And Properties Of Composite Silicon Carbide Ceramics Macroporous Support

High-temperature dust filtration system has a significant impact on the stable operation and generation efficiency of the power plant, which is a key subsystem of integrated gasification combined cycle generating unit. Porous ceramic tube with an asymmetric filter structure is the core component of the dust removal system. It is consist of filter membranes for dust filtration and the support for carrying the filter membrane. Mechanical strength and pore structure of the support have a decisive impact on the life of dust removal system, filtration efficiency and filtering accuracy.In this paper, we focus on producing a silicon carbide composite porous ceramic support with excellent strength and high porosity. The influence of body molding pressure, composition and content of raw materials for ceramic binder, sintering atmosphere, sintering temperature, pore forming method on the microstructure and properties have been systematically studied. The relationship between porosity and bending strength of the supporting body has been depth investigated. Porous ceramic samples were prepared with high strength and high porosity. The result exhibits that the mullite bonded silicon carbide porous ceramic support with the flexural strength41.0MPa, porosity44.9%can be obtained by using the process technology parameters of silicon carbide particle size23μｍ, bauxite dosage30wt%, graphite addition10wt%, green body molding pressure30MPa, sintered in air at1400℃.In order to reduce formation temperature of the main binder phase mullite and improve its crystalline morphology, the first silicon carbide powder is mixed with silica and polyvinyl butyral for granulation, sintered in a non-oxidizing atmosphere, SiC composites porous ceramic support were prepared by simulating the in-situ reaction bonding technology. Influence of aluminum fluoride trihydrate addition and sintering temperature on the microstructure and properties have been systematic study. The porous silicon carbide composite ceramic support with the flexural strength31.1MPa, porosity42.8%can be obtained by using the process technology parameters of silicon carbide (6μm) content39.7wt%, silica content17.0wt%, nano-alumina content43.3wt%of the mix,4wt%of aluminum fluoride trihydrate, body molding pressure36MPa, particle stacking into hole, sintering temperature1300℃. The phase composition is mainly silicon carbide, mullite, corundum, and a small amount of cristobalite.